A GIANT CONODONT WITH PRESERVED MUSCLE-TISSUE FROM THE UPPER ORDOVICIAN OF SOUTH-AFRICA

AN exceptionally preserved new specimen of the giant conodont Promissu m pulchrum reveals details of the trunk musculature, feeding apparatus and eyes, High-fidelity resolution of ultrastructural features of the trunk myomeres provides the first conclusive evidence of muscle-fibre organization and orientation in an extinct agnathan. The presence of fibrous extrinsic eye muscles confirms the degree of encephalization o f the conodonts and is consistent with a cladistic position crownwards of the myxinoids. The soft tissues are uniquely preserved as illite a nd mixed-layer clay minerals.